Merge pull request scikit-learn#6611 from maniteja123/chebyshev_doc

[MRG] DOC: Correct some errors in chebyshev distance

Author: MechCoder

sklearn/neighbors/dist_metrics.pyx

@@ -130,7 +130,7 @@ cdef class DistanceMetric:
  -------------- -------------------- -------- -------------------------------
  "euclidean" EuclideanDistance - ``sqrt(sum((x - y)^2))``
  "manhattan" ManhattanDistance - ``sum(|x - y|)``
- "chebyshev" ChebyshevDistance - ``sum(max(|x - y|))``
+ "chebyshev" ChebyshevDistance - ``max(|x - y|)``
  "minkowski" MinkowskiDistance p ``sum(|x - y|^p)^(1/p)``
  "wminkowski" WMinkowskiDistance p, w ``sum(w * |x - y|^p)^(1/p)``
  "seuclidean" SEuclideanDistance V ``sqrt(sum((x - y)^2 / V))``
@@ -499,7 +499,7 @@ cdef class ManhattanDistance(DistanceMetric):
 
 #------------------------------------------------------------
 # Chebyshev Distance
-# d = max_i(abs(x_i), abs(y_i))
+# d = max_i(abs(x_i - y_i))
 cdef class ChebyshevDistance(DistanceMetric):
  """Chebyshev/Infinity Distance